Lignin is an abundant source of aromatics, and the depolymerization of lignin provides significant potential for producing high-value chemicals. Selective hydrogenolysis of the C–O ether bond in lignin is an important strategy for the production of fuels and chemical feedstocks. In our study, catalytic hydrogenolysis of lignin model compounds (β-O-4, α-O-4 and 4-O-5 model compounds) over Ni₃S₂-CS catalysts was investigated. Hence, an array of 2D carbon nanostructure Ni₃S₂-CSs-X-Y derived catalysts were produced using different compositions at different temperatures (X = 0 mg, 0.2 mg, 0.4 mg, 0.6 mg, and 0.8 mg; Y = 600 °C, 700 °C, 800 °C, and 900 °C) were prepared and applied for hydrogenolysis of lignin model compounds and depolymerization of alkaline lignin. The highest conversion of lignin model compounds (β-O-4 model compound) was up to 100% and the yield of the obtained corresponding ethylbenzene and phenol could achieve 92% and 86%, respectively, over the optimal Ni₃S₂-CSs-0.4-700 catalyst in iPrOH at 260 °C without external H₂. The 2D carbon nanostructure catalysts performed a good dispersion on the surface of the carbon nanosheets, which facilitated the cleavage of the lignin ether bonds. The physicochemical characterization studies were carried out by means of XRD, SEM, TEM, H₂-TPR, NH₃-TPD, Raman and XPS analyses. Based on the optimal reaction conditions (260 °C, 4 h, 2.0 MPa N₂), various model compounds (β-O-4, α-O-4 and 4-O-5 model compounds) could also be effectively hydrotreated to produce the corresponding aromatic products. Furthermore, the optimal Ni₃S₂-CSs-0.4-700 catalyst could be carried out in the next five consecutive cycle experiments with a slight decrease in the transformation of lignin model compounds.

In this work, novel Ni-based catalysts supported on a porous carbon matrix were prepared using a simple hydrothermal method, and studied for the selective hydrotreatment of triolein. Three different catalysts were investigated, including Ni@C-BTC, Ni@C-DHTA and Ni@C-PTA. Of the catalysts studied, the Ni@C-BTC catalyst could achieve the highest conversion (up to 90%) and an excellent cracking ratio (4.61) under moderate reaction conditions (320 °C, 3 MPa, 4 h) in cyclohexane. In addition, other Ni-based catalysts prepared under different temperatures were investigated to study the influence of the calcined temperature on the activity of Ni-based catalysts. The influence of the temperature, H₂ pressure, time and catalyst loading amount was investigated for the best performing catalyst (Ni@C-BTC-400). The detailed physicochemical characterization was carried out by means of XRD, SEM, TEM, BET, NH₃-TPD, Raman and XPS analysis. In the end, the optimal Ni@C-BTC-400 catalyst could be recycled magnetically, and efficiently applied in the next run for four consecutive recycling tests in the hydrotreatment of triolein.

Biomass appears to be a potential candidate for the preparation of porous carbon materials with wide applications for catalytic fields due to its low price, green sustainability and natural hierarchical porous structure. Here, we designed a novel Ni_xCu_y/BC catalyst with a unique hollow sphere structure derived from a biomass puffball, which exhibited a superior catalytic transfer hydrodeoxygenation of VAN to value-added MMP products with an ∼100% vanillin (VAN) conversion and over 88% selectivity of 2-methoxy-4-methylphenol (MMP) products in the absence of additional hydrogen. The good catalytic activity performance of the Ni_xCu_y/BC catalysts was attributed to the NiCu alloy with a unique hollow sphere structure, high dispersion and electron transfer. Density functional theory (DFT) calculation results also indicated NiCu alloy as the main catalytic sites. This work not only provided a cheap and efficient hydrodeoxygenation catalyst for VAN hydrodeoxygenation, but also offered new insights for designing novel and unique biomass-based carbon materials for biomass utilizations or other widespread applications.